“Episode of 11 is sort of a one-hander,” Moffat says of the show, which is titled “Heaven Sent” and which he wrote. “It’s Capaldi on his own. It’s one of the strangest, and most atmospheric, and creepiest episodes that we’ve done, with the Doctor monologuing to stay alive.”

According to the official synopsis supplied by BBC America, the Rachel Talalay-directed episode will find the Doctor facing the greatest challenge of his many lives “while trapped in a world unlike any other he has seen. Pursued by the fearsome creature known only as the Veil, he must attempt the impossible. If he makes it through, Gallifrey is waiting …”

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Moffat also talked about the effect the loss of Clara will have on the Doctor, who is played by Peter Capaldi. ”Losing regular characters always kicks the living crap out of the Doctor,” says the showrunner. “He is, at the end, a very emotional man. We give him a particularly hard time with that.”